Typically, access to what is commonly referred to as "the internet" requires a data channel between a user terminal and an access provider. The access provider serves as a gateway for exchange of data between the user terminal and the various nodes which together comprise the internet.
Many types of connections between the customer and an access provider are now available, each characterized by varying levels of convenience, expense and transmission efficiency. Currently, most residential users access the internet with a conventional modem that operates at speeds up to 28.8 kilobits per second (Kbps). Such users access an internet service provider or an online service provider by establishing a circuit-switch connection through the public switched telephone network (PSTN). Point-to-point protocol (PPP) sessions to the internet access point are maintained during the duration of the circuit switch connection.
Integrated Services Digital Network (ISDN) lines are increasingly being used to access the internet with a much faster transmission speed than provided by conventional 28.8 Kbps modems. In the future, ADSL modems and cable modems are likely to offer alternative means for accessing the internet.
Primarily due to the increased use of mobile terminals, such as "laptop" or portable computers, there is an increasing demand for access to the internet from areas in which no wire terminal is accessible to the user. Some cellular systems attempt to meet this need by providing wireless internet access. For example, CDPD (Cellular Digital Packet Data) is a packet data mode for analog cellular systems which provides data transmission suitable for access to the internet. Other wireless networks, such as GSM, are also becoming available which support communication through the internet.
While providing greater convenience in terms of user mobility, conventional wireless networks are limited in significant respects. For example, they generally are expensive relative to communication over standard telephone lines. Moreover, they are characterized by a relatively low data transmission rate (typically between 9.6 and 19.2 Kbps). Further, even yet-to-be implemented systems are relatively inefficient with respect to usage. For example, GSM will require 200 Khz spacings on both uplink and downlink, thus permitting only twenty-five frequency channels in a 10 MHz system.
In summary, among the above-described conventional methods for accessing the internet, communication by modem over the PSTN is relatively inexpensive, but lacks the high speed offered by ISDN lines or the convenience of wireless cellular networks. ISDN lines provide greater efficiency through faster transmission rates, but are more expensive than a standard telephone connection and, again, less convenient to use than wireless cellular systems. While more convenient, wireless communication is limited in terms of both cost and transmission speed.
In view of the foregoing, there is a need to provide a system and method for accessing the internet which provides the speed of ISDN based systems and the convenient accessibility afforded by wireless systems while preserving spectral efficiency.